For a lot of parents, the most challenging thing about back-to-school isn't shopping for the coolest jeans or hunting down the perfect backpack (how many have you looked at?). It's packing lunches. Weeks and weeks of lunches.

So if you can pack a healthy lunch most days, it's worth it -- and not just for your kids' bodies, but also for their grades. A mid-day fuel-up that includes whole grains, fiber, and protein (a combo that digests gradually) supplies the brain with a steady stream of energy -- the exact opposite of the sugar rush and follow-up energy crash that high-carb junk foods produce in kids.

The trick, of course, is to create nutritious but delicious lunches that kids will eat, not toss or trade. How?

First, get them to pitch in -- if they help choose the contents, they're more likely to chow down.

Second, don't worry about every lunch being a perfectly balanced meal. "If your child's intake over the course of a week, on most weeks, is overall balanced, it's fine," says Dr. Jen.

Third, ask them to bring home anything they didn't eat (baby carrots, half a sandwich) -- no guilt trips! It's a good way to judge what works at lunchtime and what doesn't.

As for creative ideas, we've got a bunch, including several Dr. Jen has devised for her own three kids. Print them out and post on the fridge for instant AM inspiration.

Add fun with shapes: For young ones, use large cookie cutters to make star-shaped sandwiches on birthdays, ghosts at Halloween, and snowmen in December.

Make do-it-yourself stacks: Forget those highly processed lunch kits from the deli section. Put whole-wheat crackers, a favorite cheese or two, and lean meat in separate bags; add a mustard packet, and let kids make their own snack stacks when the time comes.

Make it brunch: There's nothing wrong with a box of multi-grain cereal, a container of berries, and a thermos of milk for lunch if that's what your kid really wants. Says Dr. Jen: "Most kids tend to hate at least one thing -- say green beans -- and devour tons of another, like their favorite cereal. Don't worry; it will pass."

Change up the bread: For a kid with a sweet tooth, how about low-fat cream cheese with apple slices on cinnamon-raisin bread? For an adventurous teen, try turkey and cheddar on rye with chutney.

Stuff it: Cut whole-wheat pitas in half, line them with lettuce leaves, and stuff them with hummus and shredded carrots...chicken slices and honey mustard...egg salad and Canadian bacon (a lean meat).
For veggie lovers (hey, many kids experiment with vegetarianism): Load a container with leafy greens, chopped veggies, and chickpeas. Add a packet of salad dressing and whole-grain pretzels or sesame crackers.

Make it a sub. Or a burrito: Fill a thermos with sliced-up meatballs and tomato sauce. Pack a sliced whole-wheat roll for a hot sub sandwich on the first cool day. Or fill the thermos with chicken-and-bean taco filling; pack whole-wheat tortillas and a bag of shredded lettuce and cheese.

Always throw in some fruit: Fresh is ideal, but stock up on sealed fruit cups (packed in juice, not syrup) and raisin boxes for that morning when there's not a tangerine in sight. "Take every opportunity to get fruits and veggies into your child's stomach," urges Dr. Jen.

Tuck in a "real" dessert: Restricting treats entirely can make kids obsess over them and lead to binging and weight problems. Just choose desserts with redeeming qualities: whole-grain fig or strawberry Newtons, banana-oatmeal muffins, a few dark chocolate Kisses (dark chocolate is rich in the same protective antioxidants found in apples and grapes).

What if you do everything right and your child brings home an untouched lunch box? Don't flip. "Not only do all kids go through stages," says Dr. Jen, "but at times, they will honestly not be hungry. Usually, this happens in a dormant phase of their growth cycle. It's okay for them not to eat much then. Just brace yourself: The next thing you know, they'll be ravenous and you won't be able to keep enough food in the house."

Need one last motivator? Think of this on those mornings when you're waffling: Getting kids in the habit of eating plenty of fruits and vegetables will benefit them for years to come. If they keep it up into adulthood, when they turn 40, their RealAge could actually be 36. Now that's a nice birthday present!